On Mon, Jul 19, 2021 at 05:13:10PM +0200, Christoph Hellwig wrote:
> On Mon, Jul 19, 2021 at 04:02:30PM +0100, Matthew Wilcox wrote:
> > > + if (iomap->type == IOMAP_INLINE) {
> > > + iomap_read_inline_data(inode, page, iomap, pos);
> > > + plen = PAGE_SIZE - poff;
> > > + goto done;
> > > + }
> >
> > This is going to break Andreas' case that he just patched to work.
> > GFS2 needs for there to _not_ be an iop for inline data. That's
> > why I said we need to sort out when to create an iop before moving
> > the IOMAP_INLINE case below the creation of the iop.
> >
> > If we're not going to do that first, then I recommend leaving the
> > IOMAP_INLINE case where it is and changing it to ...
> >
> > if (iomap->type == IOMAP_INLINE)
> > return iomap_read_inline_data(inode, page, iomap, pos);
> >
> > ... and have iomap_read_inline_data() return the number of bytes that
> > it copied + zeroed (ie PAGE_SIZE - poff).
>
> Returning the bytes is much cleaner anyway. But we still need to deal
> with the sub-page uptodate status in one form or another.
There is another iomap_read_inline_data() caller as in:
+static int iomap_write_begin_inline(struct inode *inode, loff_t pos,
+ struct page *page, struct iomap *srcmap)
+{
+ /* needs more work for the tailpacking case, disable for now */
+ if (WARN_ON_ONCE(pos != 0))
+ return -EIO;
+ if (PageUptodate(page))
+ return 0;
+ iomap_read_inline_data(inode, page, srcmap, pos);
+ return 0;
+}
I'd like to avoid it as (void)iomap_read_inline_data(...). That's why it
left as void return type.
Anyway, let's check if it works correctly first. I think it's a high
priority stuff, and EROFS uncompressed cases can be entirely cleaned
up with iomap then.
Thanks,
Gao Xiang
